Hitherto, as a cover for an air conditioning device for a vehicle, there is known a cover including an arch-like plate, reinforcing members provided on the outer side of the plate, and a heat insulating material provided on the inner side of the plate (see Patent Literature 1, for example).
On the other hand, a fiber reinforced plastic (FRP) sandwich panel including a foamed material as a core is known to be capable of light-weighting while keeping stiffness and to have excellent heat insulating property (see Patent Literature 2, for example).